What’s the Humidity in my Guitar Case? Part 2.

I’ve been thinking a lot about my recent post about the D’Addario Humiditrak – Bluetooth Humidity and Temperature sensor. I was impressed with the concept of monitoring multiple guitars (or other instruments) while they are stored in their cases. It’s something I’ve tried to do myself. But my solutions used store bought, general purpose, inexpensive humidity monitors. I could monitor the humidity in the guitar case from a wall or desk master unit without opening the case. But I couldn’t automatically see graphs of the humidity and temperature over time. I couldn’t monitor the conditions from my phone or computer. Improvements in technology should make this possible. I was excited about the Humiditrak. But after doing thinking and more research, I wonder if this product is ready for prime-time. I also question the cost/benefit ratio. Finally, the negative user reviews are disturbing. So, today’s post is about alternatives and what I think about the state of the art of monitoring temperature and humidity in your guitar case.

Do you need to Monitor?

Before you invest in humidity monitors for you guitar cases, you should consider whether you really need to monitor the environment in the case. Maybe you always keep your guitars in their cases and always use the D’Addario Humidpak system which allegedly keeps the inside of the case at a constant humidity between 45 and 50%. If you play your guitars frequently and always check to make sure the Humidipak pouches haven’t dried out, then you are (probably) good.

Analog Monitors

The D’Addario Humiditrak is a high-tech solution to monitor your guitar case and send the results to your phone by bluetooth. But simple analog hygrometers that can be placed in your guitar case are a low cost, low tech solution to monitoring. Getting the humidity and temperature on your smartphone is easy and quick but opening your guitar case and seeing the results is less expensive and probably just as reliable if you remember to check regularly.

A variation on simple analog dial hygrometers are models that can be inlayed into the top of the case so you can monitor the temperature and humidity inside while the case is closed. I’ve seen cases with this type of hygrometer 1 built-in in the past but couldn’t find one on Amazon while researching this article. I’m not sure I would want to risk damaging my guitar case to install this on the outside, but maybe you have a luthier you trust who could do it.

Digital Monitors

The biggest disadvantage of a digital hygrometer is they need to have one or more batteries to operate. But the advantage is they are (probably) more accurate and often just as inexpensive. In fact, it is more difficult to find an analog, non-battery powered monitor than it is a digital monitor. The digital monitors come in all sizes and shapes.

The AcuRite 01080M Pro Accuracy Temperature & Humidity Monitor with Alarms shown below is currently $19.99. There are two other less expensive models without alarms but having an audible alarm go off when conditions are dry seems like a good way to keep on top of humidity without the use of a remote sensor. (Image links to Amazon product page).

Some other moderately priced humidity gauges for instrument cases are shown below. The first 3 are intended to be used in instrument cases. I’ve been using the AcuRite monitor for several years to monitor the rooms in my house, but they are small enough to fit into an instrument case. You just have to find a way to secure them so they don’t bounce around.

Wireless Monitors

Wireless humidity (and temperature) monitors make tracking the condition in your guitar case easy. The newest, such as the Humiditrak, will send the conditions to your phone or tablet. But the convenience is offset by technical problems some experience. I’ve had several indoor/outdoor thermometers/hygrometers that wirelessly sent a master unit the condition measured at one or more remote units. When they worked, it was great to check the conditions in my guitar cabinet or the weather outside. But the master and remote occasionally became disconnected and sometimes had problems reconnecting. That was frustrating.

Ideally, you should be able to monitor the humidity and temperature in your guitar case from your phone regardless of where you are. But most of the current models that connect to your phone do so by bluetooth and will only connect if you are nearby. Those that offer access via the internet require a master unit that will connect to your wifi. The results are sent to the manufacturer’s website. You need an account to see your results. You may have to pay for a subscription to get alerts or all of the available data.

The advantage of any of the monitors designed for guitar or instruments is they usually have some way to secure the monitor in the case so the monitor doesn’t bang against your instrument. If you purchase a monitor that wasn’t designed with expensive musical instruments in mind, you will have to find a way (velcro?) to secure the monitor so it doesn’t damage your guitar but can still get an accurate reading.

The SensorPush Wireless Thermometer / Hygrometer below is essentially the same concept as the Humiditrak from D’Addario. The remote sensor sends reading via bluetooth to your phone. It doesn’t have a way to secure it in your guitar case because that wasn’t where it was designed to work. But if you can figure a way, it is the same cost. It currently has many more user reviews on Amazon than the Humidtrak and the reviews are better (over four stars average at this time).

If you are willing to do without a phone app to monitor your guitar case humidity but still want remote monitoring so you don’t have to open each guitar case to check on an inside monitor, there are several interesting and cost effective options. The Ambient Weather WS-10 Wireless Indoor/Outdoor 8-Channel Thermo-Hygrometer with Three Remote Sensors allows you to monitor a room plus three guitar cases (or four rooms) for about $55. You can purchase additional sensors for under $15 each. This product currently has an average 4.1 star rating out of 579 customer reviews. Compare this to some competitors to see that not all products and companies have the same quality. You will have to velcro or otherwise secure the monitors in the cases to prevent damage.

The same company, Ambient, makes a number of more expensive units. The main feature of the better units is a larger, more complex display. The model below, the Ambient Weather WS-3000-X3 Thermo-Hygrometer Wireless Monitor with 3 Remote Sensors, shows graphs of continuous monitoring. The current price is $84.95 with 3 remotes and $117.95 with 5 remotes.

Calibrating a Hygrometer

Just because you purchase a new hygrometer doesn’t mean it’s reading will be accurate. If your hygrometer is old, it is even more likely that the reading will not correspond to the actual relative humidity. Some hygrometers have an adjustment to set the reading when calibrated. Otherwise you will just have remember to subtract or add a certain number to correct the reading.

I’ve written about how to calibrate a hygrometer. The ususal method depends on creating an enclosed space that contains specific salts, dissolved in water until no more will dissolve. You will know the solution is saturated if you can see undissolved salt crystals in the solution. The trick is that different salt solutions produce specific humidities in sealed chambers. Temperature affects the humidity too, but not as much as you would think. The proper solution at room temperature should be good.

Here are the salts you should know:

  • Table salt, NaCl, produces a relative humidity of 75%.
  • Potassium Carbonate K2CO3 (not Potassium Bicarbonate) is the most useful but difficult to find. It produces a relative humidity of 43%. Search Google Shopping for Potassium Carbonate.
  • Magnesium Chloride produces a relative humidity of about 33%.

You can purchase kits with table salt and/or magnesium chloride to make it easier to calibrate your hygrometer.


As much as I like the idea of monitoring my guitars from my phone, I don’t think that technology is sophisticated and reliable enough yet. I am currently thinking about the AcuRite 01080M Pro Accuracy Temperature & Humidity Monitor with Alarms as being the best, cost-effective method to monitor my instruments. I like the idea of an audible alarm when things get too dry. My second choice would be the Ambient Weather WS-10 Wireless Indoor/Outdoor 8-Channel Thermo-Hygrometer with Three Remote Sensors. Both of these choices requires me to secure the device or sensor to keep my instruments from being dinged by flying humidity gauges. Which is why my third choice is a simple, digital, in-case guitar humidity monitor such as the Oasis OH-2.

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  1. Hygrometer: a device to monitor humidity, i.e., a humidity gauge or monitor.

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